Several noninfectious, nontraumatic disorders cause orbital inflammation in children that may simulate infection or an orbital mass lesion. Thyroid eye disease, the most common cause of proptosis in adults, rarely occurs in prepubescent children but occasionally affects adolescents. Bilateral orbital inflammation may occur with sarcoidosis.
Nonspecific orbital inflammation
Nonspecific orbital inflammation (NSOI) (also known as orbital pseudotumor, idiopathic orbital inflammatory syndrome) is an inflammatory cause of proptosis in childhood that differs significantly from the adult form. The typical pediatric presentation is acute and painful, more closely resembling orbital cellulitis than tumor or thyroid eye disease (Fig 18-14). NSOI is often bilateral and may be associated with systemic manifestations such as headache, nausea, vomiting, and lethargy. Uveitis is frequently present and occasionally constitutes the dominant manifestation. Imaging studies may show increased density of orbital fat, thickening of posterior sclera and the Tenon layer, or enlargement of extraocular muscles. The lacrimal gland is often involved. Sinusitis is typically not present. Systemic treatment with a corticosteroid usually provides prompt and dramatic relief. Recurrent disease is common. A slow tapering of corticosteroid dosage is usually required to prevent recurrence.
Figure 18-13 Mucormycosis, left orbit.
Figure 18-14 Bilateral nonspecific orbital inflammation (orbital pseudotumor) in an 11-year-old boy with a 1-week history of eye pain. Ocular rotation was markedly limited in all directions. CT confirmed proptosis and showed enlargement of all extraocular muscles. Laboratory workup was negative for thyroid disease and rheumatologic disorders. Complete resolution occurred after 1 month of corticosteroid treatment.
Orbital myositis describes NSOI that is confined to one or more extraocular muscles. The clinical presentation depends on the amount of inflammation. Diplopia, conjunctival chemosis, and orbital pain are common. Symptoms can be subacute or progress rapidly. Vision is rarely impaired unless massive muscle enlargement is present. Imaging studies show diffusely enlarged muscles with the enlargement extending all the way to the insertion (unlike in thyroid myopathy, which mainly involves the muscle belly). Corticosteroid treatment usually produces rapid relief of symptoms. Prolonged treatment is often necessary, and recurrence is common.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.